CVE-2016-4014 in Netweaver Java AS
Summary
by MITRE
XML external entity (XXE) vulnerability in the UDDI component in SAP NetWeaver JAVA AS 7.4 allows remote attackers to cause a denial of service via a crafted XML request, aka SAP Security Note 2254389.
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Analysis
by VulDB Data Team • 06/26/2024
The vulnerability identified as CVE-2016-4014 represents a critical XML external entity (XXE) flaw within the UDDI component of SAP NetWeaver JAVA Application Server version 7.4. This vulnerability resides in the Universal Description Discovery and Integration framework which serves as a registry for web services within the SAP ecosystem. The XXE vulnerability specifically affects how the system processes XML input data, creating a pathway for malicious actors to exploit the underlying XML parser configuration. The issue manifests when the UDDI component fails to properly validate and sanitize XML requests received from external sources, allowing attackers to craft specially formatted XML documents that trigger unintended behavior within the application server.
The technical exploitation of this vulnerability occurs through the manipulation of XML processing directives that reference external entities or resources. When a malicious XML request is submitted to the vulnerable UDDI component, the XML parser attempts to resolve external entity references, potentially causing the system to access unauthorized resources or consume excessive computational resources. This can lead to resource exhaustion, application instability, and ultimately a denial of service condition that impacts legitimate users and business operations. The vulnerability is particularly concerning because it operates at the XML parsing layer, where the attack can be executed without requiring authentication or elevated privileges, making it accessible to remote attackers.
The operational impact of this vulnerability extends beyond simple denial of service conditions to encompass potential data exposure and system instability. Attackers can leverage the XXE vulnerability to perform various malicious activities including information disclosure through out-of-band data retrieval, internal network reconnaissance by accessing local files, and resource exhaustion attacks that can bring the entire UDDI service to a halt. The vulnerability affects the core infrastructure components of SAP NetWeaver JAVA AS, which means that organizations relying on UDDI for service discovery and integration face significant operational risks. Additionally, the denial of service condition can disrupt business-critical processes that depend on web service registration and discovery mechanisms, potentially causing cascading failures throughout the enterprise IT environment.
Organizations can mitigate this vulnerability through several approaches that align with established cybersecurity frameworks and best practices. The primary mitigation strategy involves implementing proper XML input validation and sanitization within the UDDI component, ensuring that external entity references are disabled or properly restricted. SAP released security note 2254389 which provides specific guidance for patching and configuration changes to address this vulnerability. Organizations should also implement network segmentation and access controls to limit exposure of the UDDI component to untrusted networks. The mitigation approach should follow the principle of least privilege and adhere to the CWE-611 vulnerability classification which specifically addresses improper restriction of XML external entity references. Additionally, implementing web application firewalls and XML validation tools can provide additional layers of protection against XXE attacks, aligning with ATT&CK technique T1213 for credential access and T1499 for network denial of service attacks. Regular security assessments and vulnerability scanning should be conducted to ensure that similar vulnerabilities are not present in other components of the SAP environment.